Bogdan Krilov was a medical doctor that had mastered the art of memory manipulation, being able to implant false memories in his victims, change their memories, or erase his victim's memory. Krilov sold his services to the black market and was hired to erase the memories of witnesses, destroying the prosecution's case. Krilov erased Elizabeth Keen's memories about the night of the fire.
At 1 point he met Victor Skovic.
Harold Cooper mentions that Krilov has agreed to testify.
He was in solitary confinement at ADX Florence. He was released to aid Red in finding Ilya Koslov as he knew Victor Skovic. Donald Ressler forced Skovic to erase parts of Krilov's memories before taking him back to prison.